'\" et
.TH PTHREAD_DETACH "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\"
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
.\"
.SH NAME
pthread_detach
\(em detach a thread
.SH SYNOPSIS
.LP
.nf
#include <pthread.h>
.P
int pthread_detach(pthread_t \fIthread\fP);
.fi
.SH DESCRIPTION
The
\fIpthread_detach\fR()
function shall indicate to the implementation that storage for the
thread
.IR thread
can be reclaimed when that thread terminates. If
.IR thread
has not terminated,
\fIpthread_detach\fR()
shall not cause it to terminate.
.P
The behavior is undefined if the value specified by the
.IR thread
argument to
\fIpthread_detach\fR()
does not refer to a joinable thread.
.SH "RETURN VALUE"
If the call succeeds,
\fIpthread_detach\fR()
shall return 0; otherwise, an error number shall be returned to
indicate the error.
.SH ERRORS
The
\fIpthread_detach\fR()
function shall not return an error code of
.BR [EINTR] .
.LP
.IR "The following sections are informative."
.SH EXAMPLES
None.
.SH "APPLICATION USAGE"
None.
.SH RATIONALE
The
\fIpthread_join\fR()
or
\fIpthread_detach\fR()
functions should eventually be called for every thread that is created
so that storage associated with the thread may be reclaimed.
.P
It has been suggested that a ``detach'' function is not necessary; the
.IR detachstate
thread creation attribute is sufficient, since a thread need never be
dynamically detached. However, need arises in at least two cases:
.IP " 1." 4
In a cancellation handler for a
\fIpthread_join\fR()
it is nearly essential to have a
\fIpthread_detach\fR()
function in order to detach the thread on which
\fIpthread_join\fR()
was waiting. Without it, it would be necessary to have the handler do
another
\fIpthread_join\fR()
to attempt to detach the thread, which would both delay the cancellation
processing for an unbounded period and introduce a new call to
\fIpthread_join\fR(),
which might itself need a cancellation handler. A dynamic detach is
nearly essential in this case.
.IP " 2." 4
In order to detach the ``initial thread'' (as may be desirable in
processes that set up server threads).
.P
If an implementation detects that the value specified by the
.IR thread
argument to
\fIpthread_detach\fR()
does not refer to a joinable thread, it is recommended that the
function should fail and report an
.BR [EINVAL] 
error.
.P
If an implementation detects use of a thread ID after the end of its
lifetime, it is recommended that the function should fail and report an
.BR [ESRCH] 
error.
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IR "\fIpthread_join\fR\^(\|)"
.P
The Base Definitions volume of POSIX.1\(hy2017,
.IR "\fB<pthread.h>\fP"
.\"
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
.PP
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .